Switch to Go 1.23+ stdlib maps/slices packages

Use the maps and slices packages from the Go standard library instead of
the respective golang.org/x/exp packages. Also see
https://go.dev/doc/go1.23#iterators.

Author: tklauser

examples/scratch-env/go.mod

@@ -40,7 +40,6 @@ require (
 	github.com/prometheus/procfs v0.15.1 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
-	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56 // indirect
 	golang.org/x/net v0.30.0 // indirect
 	golang.org/x/oauth2 v0.23.0 // indirect
 	golang.org/x/sync v0.8.0 // indirect

examples/scratch-env/go.sum

@@ -112,8 +112,6 @@ go.uber.org/zap v1.27.0/go.mod h1:GB2qFLM7cTU87MWRP2mPIjqfIDnGu+VIO4V/SdhGo2E=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56 h1:2dVuKD2vS7b0QIHQbpyTISPd0LeHDbnYEryqj5Q1ug8=
-golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56/go.mod h1:M4RDyNAINzryxdtnbRXRL/OHtkFuWGRjvuhBJpk2IlY=
 golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=

go.mod

@@ -15,7 +15,7 @@ require (
 	github.com/prometheus/client_model v0.6.1
 	go.uber.org/goleak v1.3.0
 	go.uber.org/zap v1.27.0
-	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56
+	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56 // indirect
 	golang.org/x/mod v0.21.0
 	golang.org/x/sync v0.8.0
 	golang.org/x/sys v0.26.0

pkg/cache/cache.go

@@ -19,11 +19,12 @@ package cache
 import (
 	"context"
 	"fmt"
+	"maps"
 	"net/http"
+	"slices"
 	"sort"
 	"time"
 
-	"golang.org/x/exp/maps"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/meta"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -465,7 +466,7 @@ func defaultOpts(config *rest.Config, opts Options) (Options, error) {
 			if namespace == metav1.NamespaceAll {
 				config.FieldSelector = fields.AndSelectors(
 					appendIfNotNil(
-						namespaceAllSelector(maps.Keys(byObject.Namespaces)),
+						namespaceAllSelector(slices.Collect(maps.Keys(byObject.Namespaces))),
 						config.FieldSelector,
 					)...,
 				)
@@ -495,7 +496,7 @@ func defaultOpts(config *rest.Config, opts Options) (Options, error) {
 		if namespace == metav1.NamespaceAll {
 			cfg.FieldSelector = fields.AndSelectors(
 				appendIfNotNil(
-					namespaceAllSelector(maps.Keys(opts.DefaultNamespaces)),
+					namespaceAllSelector(slices.Collect(maps.Keys(opts.DefaultNamespaces))),
 					cfg.FieldSelector,
 				)...,
 			)

pkg/cache/delegating_by_gvk_cache.go

@@ -18,10 +18,11 @@ package cache
 
 import (
 	"context"
+	"maps"
+	"slices"
 	"strings"
 	"sync"
 
-	"golang.org/x/exp/maps"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -73,7 +74,7 @@ func (dbt *delegatingByGVKCache) GetInformerForKind(ctx context.Context, gvk sch
 }
 
 func (dbt *delegatingByGVKCache) Start(ctx context.Context) error {
-	allCaches := maps.Values(dbt.caches)
+	allCaches := slices.Collect(maps.Values(dbt.caches))
 	allCaches = append(allCaches, dbt.defaultCache)
 
 	wg := &sync.WaitGroup{}
@@ -100,7 +101,7 @@ func (dbt *delegatingByGVKCache) Start(ctx context.Context) error {
 
 func (dbt *delegatingByGVKCache) WaitForCacheSync(ctx context.Context) bool {
 	synced := true
-	for _, cache := range append(maps.Values(dbt.caches), dbt.defaultCache) {
+	for _, cache := range append(slices.Collect(maps.Values(dbt.caches)), dbt.defaultCache) {
 		if !cache.WaitForCacheSync(ctx) {
 			synced = false
 		}